The invention describes a winch for nautical use or for devices for lifting and lowering on a rope, comprising a fixed stator body and a rotor body fixedly connected to the stator body. The rotor body is able to rotate around a longitudinal axis to wind a rope on its outer surface. The winch is provided with a self-tailing device in turn comprising two half-pulleys, a lower half-pulley and an upper half-pulley, mounted opposite one another and coaxial to the rotor body. The two half-pulleys, at the upper portion of the outer surface of the rotor body, define a circumferential throat intended to at least partially house a winding of the rope. One half-pulley is fixed with respect to the rotor body and the other half-pulley is moveable parallel to the longitudinal axis to vary the dimensions of the circumferential throat. Advantageously, the winch comprises a device for adjusting the position of the mobile half-pulley along the longitudinal axis; the adjustment device is able to be activated by the user in real time and in all conditions of use of the winch.